The average bond enthalpy for the C-Cl bond in reaction 5 is 584 kJ/mol. The average bond enthalpy for the O-O bond in reaction 6 is 751 kJ/mol.
To calculate the average bond enthalpy for the C-Cl bond in reaction 5, we need to consider the bonds broken and formed in the reaction. One mole of Cl-Cl bonds (242 kJ/mol) and one mole of C-H bonds (435 kJ/mol) are broken. Additionally, one mole of C-Cl bonds (average bond enthalpy) is formed.
The energy required to break the bonds is the sum of the bond enthalpies for Cl-Cl and C-H, which is 242 kJ/mol + 435 kJ/mol = 677 kJ/mol. The energy released during the formation of one mole of C-Cl bonds is 93 kJ/mol.
Therefore, the average bond enthalpy for the C-Cl bond is the difference between the energy required to break the bonds and the energy released during the formation of C-Cl bonds. Average bond enthalpy for the C-Cl bond = 677 kJ/mol - 93 kJ/mol = 584 kJ/mol.
For reaction 6, the average bond enthalpy for the O-O bond can be calculated similarly. One mole of O-H bonds (463 kJ/mol) and one mole of O=O bonds (496 kJ/mol) are broken, while two moles of O=O bonds are formed. The energy required to break the bonds is 463 kJ/mol + 496 kJ/mol = 959 kJ/mol. The energy released during the formation of two moles of O=O bonds is 208 kJ/mol.
Therefore, the average bond enthalpy for the O-O bond is the difference between the energy required to break the bonds and the energy released during the formation of O=O bonds. Average bond enthalpy for the O-O bond = 959 kJ/mol - 208 kJ/mol = 751 kJ/mol.